^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * Encryption policy functions for per-file encryption support.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Copyright (C) 2015, Google, Inc.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * Copyright (C) 2015, Motorola Mobility.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * Originally written by Michael Halcrow, 2015.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) * Modified by Jaegeuk Kim, 2015.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) * Modified by Eric Biggers, 2019 for v2 policy support.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/random.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/seq_file.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <linux/string.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <linux/mount.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #include "fscrypt_private.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) * fscrypt_policies_equal() - check whether two encryption policies are the same
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) * @policy1: the first policy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) * @policy2: the second policy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) * Return: %true if equal, else %false
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) bool fscrypt_policies_equal(const union fscrypt_policy *policy1,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) const union fscrypt_policy *policy2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) if (policy1->version != policy2->version)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) return !memcmp(policy1, policy2, fscrypt_policy_size(policy1));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) static const union fscrypt_policy *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) fscrypt_get_dummy_policy(struct super_block *sb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) if (!sb->s_cop->get_dummy_policy)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) return sb->s_cop->get_dummy_policy(sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) static bool fscrypt_valid_enc_modes(u32 contents_mode, u32 filenames_mode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) if (contents_mode == FSCRYPT_MODE_AES_256_XTS &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) filenames_mode == FSCRYPT_MODE_AES_256_CTS)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) if (contents_mode == FSCRYPT_MODE_AES_128_CBC &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) filenames_mode == FSCRYPT_MODE_AES_128_CTS)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) if (contents_mode == FSCRYPT_MODE_ADIANTUM &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) filenames_mode == FSCRYPT_MODE_ADIANTUM)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) static bool supported_direct_key_modes(const struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) u32 contents_mode, u32 filenames_mode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) const struct fscrypt_mode *mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) if (contents_mode != filenames_mode) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) fscrypt_warn(inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) "Direct key flag not allowed with different contents and filenames modes");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) mode = &fscrypt_modes[contents_mode];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) if (mode->ivsize < offsetofend(union fscrypt_iv, nonce)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) fscrypt_warn(inode, "Direct key flag not allowed with %s",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) mode->friendly_name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) const struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) const char *type,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) int max_ino_bits, int max_lblk_bits)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) struct super_block *sb = inode->i_sb;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) int ino_bits = 64, lblk_bits = 64;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) * IV_INO_LBLK_* exist only because of hardware limitations, and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) * currently the only known use case for them involves AES-256-XTS.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) * That's also all we test currently. For these reasons, for now only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) * allow AES-256-XTS here. This can be relaxed later if a use case for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) * IV_INO_LBLK_* with other encryption modes arises.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) if (policy->contents_encryption_mode != FSCRYPT_MODE_AES_256_XTS) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) fscrypt_warn(inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) "Can't use %s policy with contents mode other than AES-256-XTS",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) type);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) * It's unsafe to include inode numbers in the IVs if the filesystem can
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) * potentially renumber inodes, e.g. via filesystem shrinking.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) if (!sb->s_cop->has_stable_inodes ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) !sb->s_cop->has_stable_inodes(sb)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) fscrypt_warn(inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) "Can't use %s policy on filesystem '%s' because it doesn't have stable inode numbers",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) type, sb->s_id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) if (sb->s_cop->get_ino_and_lblk_bits)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) if (ino_bits > max_ino_bits) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) fscrypt_warn(inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) "Can't use %s policy on filesystem '%s' because its inode numbers are too long",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) type, sb->s_id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) if (lblk_bits > max_lblk_bits) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) fscrypt_warn(inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) "Can't use %s policy on filesystem '%s' because its block numbers are too long",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) type, sb->s_id);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) static bool fscrypt_supported_v1_policy(const struct fscrypt_policy_v1 *policy,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) const struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) policy->filenames_encryption_mode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) fscrypt_warn(inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) "Unsupported encryption modes (contents %d, filenames %d)",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) policy->contents_encryption_mode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) policy->filenames_encryption_mode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) FSCRYPT_POLICY_FLAG_DIRECT_KEY)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) fscrypt_warn(inode, "Unsupported encryption flags (0x%02x)",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) policy->flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) if ((policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) !supported_direct_key_modes(inode, policy->contents_encryption_mode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) policy->filenames_encryption_mode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) if (IS_CASEFOLDED(inode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) /* With v1, there's no way to derive dirhash keys. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) fscrypt_warn(inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) "v1 policies can't be used on casefolded directories");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) const struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) int count = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) policy->filenames_encryption_mode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) fscrypt_warn(inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) "Unsupported encryption modes (contents %d, filenames %d)",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) policy->contents_encryption_mode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) policy->filenames_encryption_mode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) FSCRYPT_POLICY_FLAG_DIRECT_KEY |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 |
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) fscrypt_warn(inode, "Unsupported encryption flags (0x%02x)",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) policy->flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) count += !!(policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) count += !!(policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) count += !!(policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) if (count > 1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) fscrypt_warn(inode, "Mutually exclusive encryption flags (0x%02x)",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) policy->flags);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) if ((policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) !supported_direct_key_modes(inode, policy->contents_encryption_mode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) policy->filenames_encryption_mode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_64",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 32, 32))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) * IV_INO_LBLK_32 hashes the inode number, so in principle it can
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) * support any ino_bits. However, currently the inode number is gotten
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) * from inode::i_ino which is 'unsigned long'. So for now the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) * implementation limit is 32 bits.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_32",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 32, 32))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) if (memchr_inv(policy->__reserved, 0, sizeof(policy->__reserved))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) fscrypt_warn(inode, "Reserved bits set in encryption policy");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) * fscrypt_supported_policy() - check whether an encryption policy is supported
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) * @policy_u: the encryption policy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) * @inode: the inode on which the policy will be used
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) * Given an encryption policy, check whether all its encryption modes and other
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) * settings are supported by this kernel on the given inode. (But we don't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) * currently don't check for crypto API support here, so attempting to use an
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) * algorithm not configured into the crypto API will still fail later.)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) * Return: %true if supported, else %false
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) bool fscrypt_supported_policy(const union fscrypt_policy *policy_u,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) const struct inode *inode)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) switch (policy_u->version) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) case FSCRYPT_POLICY_V1:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) return fscrypt_supported_v1_policy(&policy_u->v1, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) case FSCRYPT_POLICY_V2:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) return fscrypt_supported_v2_policy(&policy_u->v2, inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) * fscrypt_new_context() - create a new fscrypt_context
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) * @ctx_u: output context
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) * @policy_u: input policy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) * @nonce: nonce to use
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) * Create an fscrypt_context for an inode that is being assigned the given
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) * encryption policy. @nonce must be a new random nonce.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) * Return: the size of the new context in bytes.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) static int fscrypt_new_context(union fscrypt_context *ctx_u,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) const union fscrypt_policy *policy_u,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) const u8 nonce[FSCRYPT_FILE_NONCE_SIZE])
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) memset(ctx_u, 0, sizeof(*ctx_u));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) switch (policy_u->version) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) case FSCRYPT_POLICY_V1: {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) const struct fscrypt_policy_v1 *policy = &policy_u->v1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) struct fscrypt_context_v1 *ctx = &ctx_u->v1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) ctx->version = FSCRYPT_CONTEXT_V1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) ctx->contents_encryption_mode =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) policy->contents_encryption_mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) ctx->filenames_encryption_mode =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) policy->filenames_encryption_mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) ctx->flags = policy->flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) memcpy(ctx->master_key_descriptor,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) policy->master_key_descriptor,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) sizeof(ctx->master_key_descriptor));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) memcpy(ctx->nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) return sizeof(*ctx);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) case FSCRYPT_POLICY_V2: {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) const struct fscrypt_policy_v2 *policy = &policy_u->v2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) struct fscrypt_context_v2 *ctx = &ctx_u->v2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) ctx->version = FSCRYPT_CONTEXT_V2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) ctx->contents_encryption_mode =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) policy->contents_encryption_mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) ctx->filenames_encryption_mode =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) policy->filenames_encryption_mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) ctx->flags = policy->flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) memcpy(ctx->master_key_identifier,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) policy->master_key_identifier,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) sizeof(ctx->master_key_identifier));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) memcpy(ctx->nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) return sizeof(*ctx);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) BUG();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) * fscrypt_policy_from_context() - convert an fscrypt_context to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) * an fscrypt_policy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) * @policy_u: output policy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) * @ctx_u: input context
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) * @ctx_size: size of input context in bytes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) * Given an fscrypt_context, build the corresponding fscrypt_policy.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) * Return: 0 on success, or -EINVAL if the fscrypt_context has an unrecognized
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) * version number or size.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) * This does *not* validate the settings within the policy itself, e.g. the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) * modes, flags, and reserved bits. Use fscrypt_supported_policy() for that.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) const union fscrypt_context *ctx_u,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) int ctx_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) memset(policy_u, 0, sizeof(*policy_u));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) if (!fscrypt_context_is_valid(ctx_u, ctx_size))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) switch (ctx_u->version) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) case FSCRYPT_CONTEXT_V1: {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) const struct fscrypt_context_v1 *ctx = &ctx_u->v1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) struct fscrypt_policy_v1 *policy = &policy_u->v1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) policy->version = FSCRYPT_POLICY_V1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) policy->contents_encryption_mode =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) ctx->contents_encryption_mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) policy->filenames_encryption_mode =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) ctx->filenames_encryption_mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) policy->flags = ctx->flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) memcpy(policy->master_key_descriptor,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) ctx->master_key_descriptor,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) sizeof(policy->master_key_descriptor));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) case FSCRYPT_CONTEXT_V2: {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) const struct fscrypt_context_v2 *ctx = &ctx_u->v2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) struct fscrypt_policy_v2 *policy = &policy_u->v2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) policy->version = FSCRYPT_POLICY_V2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) policy->contents_encryption_mode =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) ctx->contents_encryption_mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) policy->filenames_encryption_mode =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) ctx->filenames_encryption_mode;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) policy->flags = ctx->flags;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) memcpy(policy->__reserved, ctx->__reserved,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) sizeof(policy->__reserved));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) memcpy(policy->master_key_identifier,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) ctx->master_key_identifier,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) sizeof(policy->master_key_identifier));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) /* unreachable */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) /* Retrieve an inode's encryption policy */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366) static int fscrypt_get_policy(struct inode *inode, union fscrypt_policy *policy)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368) const struct fscrypt_info *ci;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) union fscrypt_context ctx;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) ci = fscrypt_get_info(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) if (ci) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) /* key available, use the cached policy */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) *policy = ci->ci_policy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) if (!IS_ENCRYPTED(inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) return -ENODATA;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383) if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) return (ret == -ERANGE) ? -EINVAL : ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) return fscrypt_policy_from_context(policy, &ctx, ret);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) static int set_encryption_policy(struct inode *inode,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) const union fscrypt_policy *policy)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) union fscrypt_context ctx;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394) int ctxsize;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) if (!fscrypt_supported_policy(policy, inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) switch (policy->version) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401) case FSCRYPT_POLICY_V1:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) * The original encryption policy version provided no way of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404) * verifying that the correct master key was supplied, which was
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) * insecure in scenarios where multiple users have access to the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406) * same encrypted files (even just read-only access). The new
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) * encryption policy version fixes this and also implies use of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) * an improved key derivation function and allows non-root users
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) * to securely remove keys. So as long as compatibility with
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 410) * old kernels isn't required, it is recommended to use the new
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 411) * policy version for all new encrypted directories.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 412) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 413) pr_warn_once("%s (pid %d) is setting deprecated v1 encryption policy; recommend upgrading to v2.\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 414) current->comm, current->pid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 415) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 416) case FSCRYPT_POLICY_V2:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 417) err = fscrypt_verify_key_added(inode->i_sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 418) policy->v2.master_key_identifier);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 419) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 420) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 421) if (policy->v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 422) pr_warn_once("%s (pid %d) is setting an IV_INO_LBLK_32 encryption policy. This should only be used if there are certain hardware limitations.\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 423) current->comm, current->pid);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 424) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 425) default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 426) WARN_ON(1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 427) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 428) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 429)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 430) get_random_bytes(nonce, FSCRYPT_FILE_NONCE_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 431) ctxsize = fscrypt_new_context(&ctx, policy, nonce);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 432)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 433) return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, NULL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 434) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 435)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 436) int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 437) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 438) union fscrypt_policy policy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 439) union fscrypt_policy existing_policy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 440) struct inode *inode = file_inode(filp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 441) u8 version;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 442) int size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 443) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 444)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 445) if (get_user(policy.version, (const u8 __user *)arg))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 446) return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 447)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 448) size = fscrypt_policy_size(&policy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 449) if (size <= 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 450) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 451)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 452) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 453) * We should just copy the remaining 'size - 1' bytes here, but a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 454) * bizarre bug in gcc 7 and earlier (fixed by gcc r255731) causes gcc to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 455) * think that size can be 0 here (despite the check above!) *and* that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 456) * it's a compile-time constant. Thus it would think copy_from_user()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 457) * is passed compile-time constant ULONG_MAX, causing the compile-time
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 458) * buffer overflow check to fail, breaking the build. This only occurred
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 459) * when building an i386 kernel with -Os and branch profiling enabled.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 460) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 461) * Work around it by just copying the first byte again...
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 462) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 463) version = policy.version;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 464) if (copy_from_user(&policy, arg, size))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 465) return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 466) policy.version = version;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 467)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 468) if (!inode_owner_or_capable(inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 469) return -EACCES;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 470)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 471) ret = mnt_want_write_file(filp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 472) if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 473) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 474)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 475) inode_lock(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 476)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 477) ret = fscrypt_get_policy(inode, &existing_policy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 478) if (ret == -ENODATA) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 479) if (!S_ISDIR(inode->i_mode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 480) ret = -ENOTDIR;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 481) else if (IS_DEADDIR(inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 482) ret = -ENOENT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 483) else if (!inode->i_sb->s_cop->empty_dir(inode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 484) ret = -ENOTEMPTY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 485) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 486) ret = set_encryption_policy(inode, &policy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 487) } else if (ret == -EINVAL ||
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 488) (ret == 0 && !fscrypt_policies_equal(&policy,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 489) &existing_policy))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 490) /* The file already uses a different encryption policy. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 491) ret = -EEXIST;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 492) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 493)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 494) inode_unlock(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 495)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 496) mnt_drop_write_file(filp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 497) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 498) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 499) EXPORT_SYMBOL(fscrypt_ioctl_set_policy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 500)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 501) /* Original ioctl version; can only get the original policy version */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 502) int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 503) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 504) union fscrypt_policy policy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 505) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 506)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 507) err = fscrypt_get_policy(file_inode(filp), &policy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 508) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 509) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 510)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 511) if (policy.version != FSCRYPT_POLICY_V1)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 512) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 513)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 514) if (copy_to_user(arg, &policy, sizeof(policy.v1)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 515) return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 516) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 517) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 518) EXPORT_SYMBOL(fscrypt_ioctl_get_policy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 519)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 520) /* Extended ioctl version; can get policies of any version */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 521) int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *uarg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 522) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 523) struct fscrypt_get_policy_ex_arg arg;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 524) union fscrypt_policy *policy = (union fscrypt_policy *)&arg.policy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 525) size_t policy_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 526) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 527)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 528) /* arg is policy_size, then policy */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 529) BUILD_BUG_ON(offsetof(typeof(arg), policy_size) != 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 530) BUILD_BUG_ON(offsetofend(typeof(arg), policy_size) !=
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 531) offsetof(typeof(arg), policy));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 532) BUILD_BUG_ON(sizeof(arg.policy) != sizeof(*policy));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 533)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 534) err = fscrypt_get_policy(file_inode(filp), policy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 535) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 536) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 537) policy_size = fscrypt_policy_size(policy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 538)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 539) if (copy_from_user(&arg, uarg, sizeof(arg.policy_size)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 540) return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 541)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 542) if (policy_size > arg.policy_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 543) return -EOVERFLOW;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 544) arg.policy_size = policy_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 545)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 546) if (copy_to_user(uarg, &arg, sizeof(arg.policy_size) + policy_size))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 547) return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 548) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 549) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 550) EXPORT_SYMBOL_GPL(fscrypt_ioctl_get_policy_ex);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 551)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 552) /* FS_IOC_GET_ENCRYPTION_NONCE: retrieve file's encryption nonce for testing */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 553) int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 554) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 555) struct inode *inode = file_inode(filp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 556) union fscrypt_context ctx;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 557) int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 558)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 559) ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 560) if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 561) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 562) if (!fscrypt_context_is_valid(&ctx, ret))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 563) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 564) if (copy_to_user(arg, fscrypt_context_nonce(&ctx),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 565) FSCRYPT_FILE_NONCE_SIZE))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 566) return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 567) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 568) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 569) EXPORT_SYMBOL_GPL(fscrypt_ioctl_get_nonce);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 570)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 571) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 572) * fscrypt_has_permitted_context() - is a file's encryption policy permitted
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 573) * within its directory?
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 574) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 575) * @parent: inode for parent directory
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 576) * @child: inode for file being looked up, opened, or linked into @parent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 577) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 578) * Filesystems must call this before permitting access to an inode in a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 579) * situation where the parent directory is encrypted (either before allowing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 580) * ->lookup() to succeed, or for a regular file before allowing it to be opened)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 581) * and before any operation that involves linking an inode into an encrypted
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 582) * directory, including link, rename, and cross rename. It enforces the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 583) * constraint that within a given encrypted directory tree, all files use the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 584) * same encryption policy. The pre-access check is needed to detect potentially
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 585) * malicious offline violations of this constraint, while the link and rename
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 586) * checks are needed to prevent online violations of this constraint.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 587) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 588) * Return: 1 if permitted, 0 if forbidden.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 589) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 590) int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 591) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 592) union fscrypt_policy parent_policy, child_policy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 593) int err, err1, err2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 594)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 595) /* No restrictions on file types which are never encrypted */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 596) if (!S_ISREG(child->i_mode) && !S_ISDIR(child->i_mode) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 597) !S_ISLNK(child->i_mode))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 598) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 599)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 600) /* No restrictions if the parent directory is unencrypted */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 601) if (!IS_ENCRYPTED(parent))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 602) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 603)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 604) /* Encrypted directories must not contain unencrypted files */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 605) if (!IS_ENCRYPTED(child))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 606) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 607)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 608) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 609) * Both parent and child are encrypted, so verify they use the same
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 610) * encryption policy. Compare the fscrypt_info structs if the keys are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 611) * available, otherwise retrieve and compare the fscrypt_contexts.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 612) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 613) * Note that the fscrypt_context retrieval will be required frequently
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 614) * when accessing an encrypted directory tree without the key.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 615) * Performance-wise this is not a big deal because we already don't
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 616) * really optimize for file access without the key (to the extent that
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 617) * such access is even possible), given that any attempted access
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 618) * already causes a fscrypt_context retrieval and keyring search.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 619) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 620) * In any case, if an unexpected error occurs, fall back to "forbidden".
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 621) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 622)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 623) err = fscrypt_get_encryption_info(parent, true);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 624) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 625) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 626) err = fscrypt_get_encryption_info(child, true);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 627) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 628) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 629)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 630) err1 = fscrypt_get_policy(parent, &parent_policy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 631) err2 = fscrypt_get_policy(child, &child_policy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 632)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 633) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 634) * Allow the case where the parent and child both have an unrecognized
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 635) * encryption policy, so that files with an unrecognized encryption
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 636) * policy can be deleted.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 637) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 638) if (err1 == -EINVAL && err2 == -EINVAL)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 639) return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 640)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 641) if (err1 || err2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 642) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 643)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 644) return fscrypt_policies_equal(&parent_policy, &child_policy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 645) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 646) EXPORT_SYMBOL(fscrypt_has_permitted_context);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 647)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 648) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 649) * Return the encryption policy that new files in the directory will inherit, or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 650) * NULL if none, or an ERR_PTR() on error. If the directory is encrypted, also
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 651) * ensure that its key is set up, so that the new filename can be encrypted.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 652) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 653) const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 654) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 655) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 656)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 657) if (IS_ENCRYPTED(dir)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 658) err = fscrypt_require_key(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 659) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 660) return ERR_PTR(err);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 661) return &dir->i_crypt_info->ci_policy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 662) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 663)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 664) return fscrypt_get_dummy_policy(dir->i_sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 665) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 666)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 667) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 668) * fscrypt_set_context() - Set the fscrypt context of a new inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 669) * @inode: a new inode
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 670) * @fs_data: private data given by FS and passed to ->set_context()
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 671) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 672) * This should be called after fscrypt_prepare_new_inode(), generally during a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 673) * filesystem transaction. Everything here must be %GFP_NOFS-safe.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 674) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 675) * Return: 0 on success, -errno on failure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 676) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 677) int fscrypt_set_context(struct inode *inode, void *fs_data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 678) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 679) struct fscrypt_info *ci = inode->i_crypt_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 680) union fscrypt_context ctx;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 681) int ctxsize;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 682)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 683) /* fscrypt_prepare_new_inode() should have set up the key already. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 684) if (WARN_ON_ONCE(!ci))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 685) return -ENOKEY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 686)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 687) BUILD_BUG_ON(sizeof(ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 688) ctxsize = fscrypt_new_context(&ctx, &ci->ci_policy, ci->ci_nonce);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 689)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 690) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 691) * This may be the first time the inode number is available, so do any
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 692) * delayed key setup that requires the inode number.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 693) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 694) if (ci->ci_policy.version == FSCRYPT_POLICY_V2 &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 695) (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 696) const struct fscrypt_master_key *mk =
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 697) ci->ci_master_key->payload.data[0];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 698)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 699) fscrypt_hash_inode_number(ci, mk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 700) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 701)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 702) return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, fs_data);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 703) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 704) EXPORT_SYMBOL_GPL(fscrypt_set_context);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 705)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 706) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 707) * fscrypt_set_test_dummy_encryption() - handle '-o test_dummy_encryption'
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 708) * @sb: the filesystem on which test_dummy_encryption is being specified
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 709) * @arg: the argument to the test_dummy_encryption option. May be NULL.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 710) * @dummy_policy: the filesystem's current dummy policy (input/output, see
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 711) * below)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 712) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 713) * Handle the test_dummy_encryption mount option by creating a dummy encryption
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 714) * policy, saving it in @dummy_policy, and adding the corresponding dummy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 715) * encryption key to the filesystem. If the @dummy_policy is already set, then
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 716) * instead validate that it matches @arg. Don't support changing it via
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 717) * remount, as that is difficult to do safely.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 718) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 719) * Return: 0 on success (dummy policy set, or the same policy is already set);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 720) * -EEXIST if a different dummy policy is already set;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 721) * or another -errno value.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 722) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 723) int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 724) struct fscrypt_dummy_policy *dummy_policy)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 725) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 726) struct fscrypt_key_specifier key_spec = { 0 };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 727) int version;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 728) union fscrypt_policy *policy = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 729) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 730)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 731) if (!arg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 732) arg = "v2";
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 733)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 734) if (!strcmp(arg, "v1")) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 735) version = FSCRYPT_POLICY_V1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 736) key_spec.type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 737) memset(key_spec.u.descriptor, 0x42,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 738) FSCRYPT_KEY_DESCRIPTOR_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 739) } else if (!strcmp(arg, "v2")) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 740) version = FSCRYPT_POLICY_V2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 741) key_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 742) /* key_spec.u.identifier gets filled in when adding the key */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 743) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 744) err = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 745) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 746) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 747)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 748) policy = kzalloc(sizeof(*policy), GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 749) if (!policy) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 750) err = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 751) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 752) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 753)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 754) err = fscrypt_add_test_dummy_key(sb, &key_spec);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 755) if (err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 756) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 757)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 758) policy->version = version;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 759) switch (policy->version) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 760) case FSCRYPT_POLICY_V1:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 761) policy->v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 762) policy->v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 763) memcpy(policy->v1.master_key_descriptor, key_spec.u.descriptor,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 764) FSCRYPT_KEY_DESCRIPTOR_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 765) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 766) case FSCRYPT_POLICY_V2:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 767) policy->v2.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 768) policy->v2.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 769) memcpy(policy->v2.master_key_identifier, key_spec.u.identifier,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 770) FSCRYPT_KEY_IDENTIFIER_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 771) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 772) default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 773) WARN_ON(1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 774) err = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 775) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 776) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 777)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 778) if (dummy_policy->policy) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 779) if (fscrypt_policies_equal(policy, dummy_policy->policy))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 780) err = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 781) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 782) err = -EEXIST;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 783) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 784) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 785) dummy_policy->policy = policy;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 786) policy = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 787) err = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 788) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 789) kfree(policy);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 790) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 791) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 792) EXPORT_SYMBOL_GPL(fscrypt_set_test_dummy_encryption);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 793)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 794) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 795) * fscrypt_show_test_dummy_encryption() - show '-o test_dummy_encryption'
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 796) * @seq: the seq_file to print the option to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 797) * @sep: the separator character to use
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 798) * @sb: the filesystem whose options are being shown
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 799) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 800) * Show the test_dummy_encryption mount option, if it was specified.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 801) * This is mainly used for /proc/mounts.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 802) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 803) void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 804) struct super_block *sb)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 805) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 806) const union fscrypt_policy *policy = fscrypt_get_dummy_policy(sb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 807) int vers;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 808)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 809) if (!policy)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 810) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 811)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 812) vers = policy->version;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 813) if (vers == FSCRYPT_POLICY_V1) /* Handle numbering quirk */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 814) vers = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 815)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 816) seq_printf(seq, "%ctest_dummy_encryption=v%d", sep, vers);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 817) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 818) EXPORT_SYMBOL_GPL(fscrypt_show_test_dummy_encryption);
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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